Stephanie Spengler

Common and distinct networks for self-referential and social stimulus processing in the human brain

Self-referential processing is a complex cognitive function, involving a set of implicit and explicit processes, complicating investigation of its distinct neural signature. The present study explores the functional overlap and dissociability of self-referential and social stimulus processing. We combined an established paradigm for explicit self-referential processing with an implicit social stimulus processing paradigm in one fMRI experiment to determine the neural effects of self-relatedness and social processing within one study. Overlapping activations were found in the orbitofrontal cortex and in the intermediate part of the precuneus. Stimuli judged as self-referential specifically activated the posterior cingulate cortex, the ventral medial prefrontal cortex, extending into anterior cingulate cortex and orbitofrontal cortex, the dorsal medial prefrontal cortex, the ventral and dorsal lateral prefrontal cortex, the left inferior temporal gyrus, and occipital cortex. Social processing specifically involved the posterior precuneus and bilateral temporo-parietal junction. Taken together, our data show, not only, first, common networks for both processes in the medial prefrontal and the medial parietal cortex, but also, second, functional differentiations for self-referential processing versus social processing: an anterior–posterior gradient for social processing and self-referential processing within the medial parietal cortex and specific activations for self-referential processing in the medial and lateral prefrontal cortex and for social processing in the temporo-parietal junction.

Decreased gray matter volume in inferior frontal gyrus is related to stop-signal task performance in alcohol-dependent patients.

Impairment in inhibitory control has been proposed to contribute to habitual alcohol use, abuse and eventually dependence. Moreover, alcohol-dependent (AD) patients have shown a loss of gray matter volume (GMV) in the brain, specifically in prefrontal regions associated with executive functions, including response inhibition. To date, no study has evaluated whether this prefrontal GMV reduction is related to response inhibition in alcohol dependence. To address this issue, we acquired high-resolution T1-weighted magnetic resonance mages from recently detoxified AD patients (n = 22) and healthy controls (HC; n = 21). Differences in local GMV between groups were assessed by means of voxel-based morphometry (VBM). Moreover, within the AD group, mean local GMV reductions were extracted and correlated with behavioral performance on the stop-signal task. We found a significantly decrease in GMV in the left inferior frontal gyrus (IFG) in AD patients compared with HC subjects. Further, mean local GMV in this area correlated positively with reaction times on go trials during the stop-signal task in AD patients. Our findings suggest that GMV losses in the IFG in AD patients are related to faster go responses on the stop-signal task.

Doing good or bad: How interactions between action and emotion expectations shape the sense of agency

The emotional consequences of our own and others’ actions can influence our agentive self-awareness in social contexts. Positive outcomes are usually linked to the self and used for self-enhancement, whereas negative outcomes are more often attributed to others. In most situations, these causal attribution tendencies seem to be immediately present instead of involving reflective interpretations of the action experience. To address the question at which level of the cognitive hierarchy emotions and action perception interact, we adopted a social reward anticipation paradigm. Here, participants or their interaction partner received positive or negative action outcomes and performed speeded attribution choices regarding causation of the action outcome. Event-Related Potential (ERP) results showed that the emotional value of an outcome already influenced the classical N1 self-attenuation effect, with reduced embodied agentive self-awareness for negative outcomes at initial sensorimotor stages. At the level of the N300, the degree of updating and affective evaluation associated with the respective attributive decision was reflected and particularly associated to attribution tendencies for positive events. Our results show an early interaction between emotion and agency processes, and suggest that self-serving cognition can be grounded in embodied knowledge from low-level sensorimotor mechanisms.

Neural alterations of fronto-striatal circuitry during reward anticipation in euthymic bipolar disorder

BACKGROUND Bipolar disorder (BD), with the hallmark symptoms of elevated and depressed mood, is thought to be characterized by underlying alterations in reward-processing networks. However, to date the neural circuitry underlying abnormal responses during reward processing in BD remains largely unexplored. The aim of this study was to investigate whether euthymic BD is characterized by aberrant ventral striatal (VS) activation patterns and altered connectivity with the prefrontal cortex in response to monetary gains and losses. METHOD During functional magnetic resonance imaging 20 euthymic BD patients and 20 age-, gender- and intelligence quotient-matched healthy controls completed a monetary incentive delay paradigm, to examine neural processing of reward and loss anticipation. A priori defined regions of interest (ROIs) included the VS and the anterior prefrontal cortex (aPFC). Psychophysiological interactions (PPIs) between these ROIs were estimated and tested for group differences for reward and loss anticipation separately. RESULTS BD participants, relative to healthy controls, displayed decreased activation selectively in the left and right VS during anticipation of reward, but not during loss anticipation. PPI analyses showed decreased functional connectivity between the left VS and aPFC in BD patients compared with healthy controls during reward anticipation. CONCLUSIONS This is the first study showing decreased VS activity and aberrant connectivity in the reward-processing circuitry in euthymic, medicated BD patients during reward anticipation. Our findings contrast with research supporting a reward hypersensitivity model of BD, and add to the body of literature suggesting that blunted activation of reward processing circuits may be a vulnerability factor for mood disorders.

Social cognition in aggressive offenders: impaired empathy, but intact theory of mind

Aggressive, violent behaviour is a major burden and challenge for society. It has been linked to deficits in social understanding, but the evidence is inconsistent and the specifics of such deficits are unclear. Here, we investigated affective (empathy) and cognitive (Theory of Mind) routes to understanding other people in aggressive individuals. Twenty-nine men with a history of legally relevant aggressive behaviour (i.e. serious assault) and 32 control participants were tested using a social video task (EmpaToM) that differentiates empathy and Theory of Mind and completed questionnaires on aggression and alexithymia. Aggressive participants showed reduced empathic responses to emotional videos of others’ suffering, which correlated with aggression severity. Theory of Mind performance, in contrast, was intact. A mediation analysis revealed that reduced empathy in aggressive men was mediated by alexithymia. These findings stress the importance of distinguishing between socio-affective and socio-cognitive deficits for understanding aggressive behaviour and thereby contribute to the development of more efficient treatments.

Alterations in neural Theory of Mind processing in euthymic patients with bipolar disorder and unaffected relatives.

Behavioral deficits in the Theory of Mind (ToM) have been robustly demonstrated in bipolar disorder. These deficits may represent an intermediate phenotype of the disease. The aim of this study was: (i) to investigate alterations in neural ToM processing in euthymic patients with bipolar disorder, and (ii) to examine whether similar effects are present in unaffected relatives of patients with bipolar disorder suggesting that ToM functional activation may be, in part, due to genetic risk for the disease.

Imagining triadic interactions simultaneously activates mirror and mentalizing systems.

Coordinated triadic interactions, involving oneself, another person, and an external object, are considered a uniquely human skill. However, the exact mechanisms underlying the ability to engage in such social interactions remain hitherto unknown. We used functional neuroimaging to investigate the neural signature of triadic interactions. For this purpose, participants viewed pictures of objects in a 3T functional magnetic resonance imaging scanner and were asked whether they could imagine this object in a social interaction with another person. We also aimed to dissociate this process from, as well as to find commonalities with, purely self-referential or other-referential processing. In all trial-types, we found activations in core mentalizing brain areas (medial prefrontal cortex, posterior cingulate cortex, precuneus and temporoparietal junction). Furthermore, triadic engagements, but not self-referential or other-referential processing, were associated with activations in classical mirror neuron areas (inferior frontal gyrus and inferior parietal lobe). Finally, mentalizing networks showed a strong functional connectivity with mirror neuron areas exclusively during triadic engagements. These results suggest that the imagined interaction of two agents is processed in a more complex neural social cognitive network than purely self- or other-referential considerations.

Interacting and dissociable effects of alexithymia and depression on empathy

Major-depressive-disorder (MDD) and alexithymia have both been associated with empathy deficits. We examined whether depression and alexithymia show dissociable or interacting effects on cognitive and emotional trait and state empathy. Healthy controls with high and low alexithymia and MDD-patients with high and low alexithymia were assessed. We used the Interpersonal-Reactivity-Index-questionnaire (IRI) for trait cognitive and emotional empathy and the Multifaceted-Empathy-Test (MET) for state cognitive and emotional empathy. Firstly, we found a main effect of alexithymia, irrespective of depression, on trait and state cognitive empathy: High alexithymia subjects showed lower scores in perspective taking (IRI) and in the cognitive-empathy-component of the MET. Secondly, we found main effects of alexithymia and depression on trait emotional empathy (IRI-subscale personal distress). Moreover, we found a significant depression-by-alexithymia-interaction on trait emotional empathy: MDD-patients showed particularly high personal distress when affected by alexithymia (IRI). Thirdly, alexithymia and depression had no impact on state emotional empathy (MET). However, analyzing positive and negative trials separately, we found more emotional empathy in MDD-patients concerning negatively valenced stimuli. Our data suggest dissociable and interacting effects of MDD and alexithymia on empathy. Importantly, except for heightened personal distress, empathy deficits in MDD-patients were entirely due to concurrent alexithymia.

Decreased medial prefrontal cortex activation during self-referential processing in bipolar mania

BACKGROUND Patients with bipolar disorder in mania exhibit symptoms pointing towards altered self-referential processing, such as decreased self-focus, flight of ideas and high distractibility. In depression, the opposite pattern of symptoms has been connected to increased activation of medial prefrontal cortex (mPFC) during self-referential processing. In this study, we hypothesized that (1) patients with mania will exhibit decreased activation in the mPFC during self-referential processing and (2) will be more alexithymic and that levels of alexithymia will correlate negatively with mPFC activation. METHODS The neural response to standardized pictures was compared in 14 patients with bipolar I disorder in mania to 14 healthy controls using blood oxygen level dependent contrast magnetic resonance imaging. Participants were asked to indicate with button press during the scanning session for each picture whether the pictures personally related to them or not. Toronto alexithymia scale (TAS) scores were recorded from all participants. RESULTS In the group analysis, patients with mania exhibited decreased activation in a predefined region of interest in the mPFC during self-referential processing compared to healthy controls. Patients with mania showed significantly higher levels of alexithymia, attributable to difficulties in identifying and describing emotions. Activation in the mPFC correlated negatively with levels of alexithymia. LIMITATIONS Results presented here should be replicated in a larger group, potentially including unmedicated patients. CONCLUSIONS The finding of decreased mPFC activation during self-referential processing in mania may reflect decreased self-focus and high distractibility. Support for this view comes from the negative correlation between higher alexithymia scores and decreased mPFC activation. These findings represent an opposite clinical and neuroimaging pattern to findings in depression.